Scabies Treatment

Topical Treatment

• Permethrin 5% Cream

Permethrin, a synthetic pyrethroid derivative.

- Thoroughly wash and dry the skin with clean cloth.
- Apply the cream into the skin from the neck to the soles of the feet, special attention to the web spaces, flexures, wrist and thigh.
- Leave the permethrin cream on the body for 8 to 12 hours.
- Wash off by taking a bath.

• Gamma benzene hexachloride 1%

- Gamma benzene hexachloride lotion is to be applied all over the body except face, after scrubbed bath and kept it for 12 to 24 hours. Apply for two consecutive days and repeat after 10 days. While taking bath whole body should be scrubbed to open up the burrows.

Contraindicated in pregnancy

• Benzyl benzoate 25 %

 - Overnight application of 25 % emulsion lotion for three consecutive nights.

• Crotamiton 10%

- An application of thin layer of 10% cream or lotion from neck to toes. 

- Second application applied after 24 hours

- Crotamition and hydrocrtisone combination is an effective treatment for nodular Scabies especially over the genitalia.

• Precipited Sulfur 

-Sulfur ointment with 6% precipitated sulfur applied to the entire body at night for three consecutive nights.

Systemic Treatment

• Ivermectin  

Ivermectin is an avermectin derivative separated from fermentation products of streptomyces avermititis  

- 12 milligrams (mg) single dose of tablet ivermectin to be repeated after 15 days.

- 200 microgram/kg single dose in children 
- Repeat dose of ivermectin after two weeks improves cure rate.

- Not recommended in children below 5 years 

-Secondary Bacterial infection with Eczematization and paraphimosis are treated before antiscabetic applications.

-Secondary infections are treated with oral erythromycin or cefadroxyl or cloxacillin .
-Antihistaminics like pheniramine maleate or levocetrizine are useful to relieve pruritus (Itching).

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Complications of Scabies

• Secondary Bacterial infection

Scabies not treated early then develops secondary bacterial infection with streptococci or staphylococi. Untreated lesions of scabis convert into pustules and bullae filled with pus. These lesions burst, get converted with purulent, yellowish crusts it is due to scrating erosion forms. 

• Erythroderma

• Infective Eczema

This condition is usually develops in infants and children. Diseased areas display erythema, edema, vasiculation, oozing and serosanguinous crusting. Face is usually involved in infants.

• Paraphimosis 

Paraphimosis is develops due to retracted edematous preputial skin which is unable to take forward. Condition is commonly seen in children. 

Eczematoid and infected

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Diagnosis of Scabies

Diagnosis of Scabies should be considered in patients with pruritus with nocturnal  exacerbation and symmetric polymorphic skin lesions in characteristics location. Particularly if there is a history of scabies in close contacts.
Burrows should be sought and unroofed with sterile needle or scalpel blade, and the scraping should be examined under microscope for the mite, its eggs or its fecal pellets.

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Atypical forms of Scabies

• Nodular Scabies

Erythematous or skin colored persistent papules and nodules occur over genitalia, axillae especially in the male . Extremely pruritic lesions. These skin lesions can not demonstrate mite or mite products.

• Norwegian or Crusted  Scabies

 Atypical rare form of Scabies that affects immunosuppressed persons (HIV infection and immuno suppressive therapy ) or those who have lost the sensation of pruritus, mentally retarded persons who are unable to take care of themselves.

Scaly erythematous and keratotic plaques over extremities, trunk, scalp and faces are characteristics of this condition.
This type of Scabies is likely to be missed without a high index of suspicion.

Norwegian Scabies

• Scabies in the 'Clean'

This type is usually present in individuals with good personal hygiene. These patients have fewer lesions, but sever pruritus. Lesions may be at atypical sites.

• Scabies in infants

 This type of Scabies shows involvement of palms and soles as well as the face and scalp.

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Clinical Manifestations (Signs and Symptoms)

• Develops after an incubation period of about four weeks.

• Severe pruritus (itching) that gets exacerbated at night.

• Presence of burrows is a sign of Scabies. Burrows are greyish and irregular, scaly lesions usually of about 3 to 15 millimeters (mm) long, generally on the intradigital spaces, but can also be seen on the flexures of the wrists, and elbows, axillary folds and genitalia.

• Small erythematous papules, escoriated papules and papulo-vesicles are often occupied by eczematous plaques, pustules or nodules, are Symmetrically distributed in the web spaces, wrists,anterior axillary folds, nipple and areola in women, periumbilical region, genitalia especially in the male, anterior  thigh, buttocks. 

• Erythematous follicular papules over anterior thigh are common in adults.

• The lesions may be infected with bacteria and folliculites, oozing and crusting are very commonly seen as localized or extensive infective eczema .

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Pathogenesis of Scabies

Scabies Mite (Adult Female)

Gravid female mites is necessary for spread (transmission) of infection. The female mites measuring 0.3 to 0.4 millimeters (mm) in length, oval in shape, they are ventrally flattened and have a convex dorsal surface. Mite have four pairs of legs.

Fertilized female mites burrow for a month superficially beneath the stratum corneum of the skin where they deposit two or three eggs per day for six to eight weeks. Larvae that hatches from these eggs mature in a series of molts in about two weeks and after that emerge to the surface of the skin, becomes adult, where they mate and subsequently reinvade the skin of the same or another host. Transmission of fertilized female mite from one person to another occurs by intimate personal contact and is facilitated by crowding, uncleanliness.

The itching and rash associated with Scabies derive from a sensitization reaction to the excreta that the mite deposit  in its burrows.

These mites can not survive off the human body for more than 48 hours and can not reproduce off the body.

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Scabies definition and Incubation Period

Definition:

Scabies is an ectoparasitic, contagious infestation caused by the mite Sarcoptes Scabies; transmitted due to close bodily contact such as sleeping and sitting together.

Incubation Period:

Incubation Period about one month passes before itching begins. Itching is due to hypersensitivity to mite antigen. Itching may persist for a few weeks even after complete treatment.

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